JP2016208603A - Rotary drive device, stepping motor and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary drive device, a stepping motor and an electronic apparatus, capable of effectively storing a lubricant at the bearing part of a revolving shaft.SOLUTION: The rotary drive device includes: a rotor having a protruding one end of a revolving shaft; and a bearing having an engaging part rotatably engaging with the one end of the revolving shaft. In the periphery of the engaging part of the bearing, there is provided a contact part, which linearly contacts to the one end tip of the revolving shaft protruding toward the end part side of the rotor, continuously along the rotation direction of the rotor, with a larger outer diameter than the engaging part. Between the contact part and the revolving shaft, there is provided a storage part for storing a lubricant which is supplied to the engaging part of the one end of the revolving shaft with the engaging part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotary drive device such as a motor, a stepping motor provided with the rotary drive device, and an electronic apparatus provided with the rotary drive device.

  Conventionally, for example, a stepping motor is known in which one end of a motor shaft inserted through a rotor magnet is received by a resin bearing and the other end of the motor shaft is received by a metal bearing (see Patent Document 1). Here, in such a motor shaft bearing, a lubricant such as oil may be interposed between the motor shaft and the bearing in order to improve slidability.

JP 2009-71974 A

  However, in the conventional motor bearing structure, for example, when a lubricant is interposed between the motor shaft and its bearing, the lubricant protrudes from the bearing portion with the rotation of the motor shaft, and more external than necessary. May be leaked.

  The present invention provides a rotary drive device, a stepping motor, and an electronic device that can effectively store a lubricant in a bearing portion of a rotary shaft.

The rotation drive device of the present invention includes: a rotating body with one end of a rotating shaft protruding; and a bearing having an engaging portion with which one end of the rotating shaft is rotatably engaged. The contact part which protrudes toward the edge part side of the said rotary body from which the one end of the said rotating shaft protruded, and the front-end | tip contacts a line contact with the edge part of the said rotary body is larger than the said engaging part. Lubricant that is provided along the rotation direction of the rotating body with an outer diameter, and is supplied to an engagement portion between one end of the rotation shaft and the engagement portion between the contact portion and the rotation shaft. A storage part for storing the agent is provided.
According to this aspect of the present invention, the lubricant can be stored between the rotating shaft and the engaging portion while reducing the influence on the rotational drive by using the contact portion between the rotating body and the abutting portion as a line contact. The lubricant can be stably supplied to the engaging portion (bearing portion) of the rotating shaft.

In the present invention, an annular intermediate member is integrally joined to the end of the rotating body, and the contact portion of the bearing is in line contact with the intermediate member. To do.
According to this aspect of the present invention, it is possible to favorably rotate the rotating body while bringing the intermediate member into line contact with the contact portion.

In the present invention, the contact portion is provided concentrically with the engagement portion of the bearing.
According to this aspect of the present invention, it is possible to minimize the influence on the rotational drive.

In the present invention, a plurality of the contact portions are provided concentrically with the engagement portion of the bearing.
According to this aspect of the present invention, the friction between the bearing and the rotating body can be reduced by providing the plurality of contact portions on the concentric circle.

In the present invention, the contact portion is provided separately from the bearing.
According to this aspect of the present invention, it is possible to form the contact portion with a material excellent in slidability regardless of the material of the bearing.

Moreover, in the said invention, the said contact part was provided continuously along the rotation direction of the said rotary body, It is characterized by the above-mentioned.
According to this aspect of the present invention, since the contact is made in a line contact state in the rotation direction of the rotating body, it is possible to minimize the influence on the rotational drive.

In the present invention, the contact portion is provided with a line contact portion and a surface contact portion along the rotation direction of the rotating body.
According to this aspect of the present invention, by providing the contact portion with the portion that makes line contact with the rotating body and the portion that makes surface contact with each other, the lubricant storage space can be stabilized while reducing the influence on the rotational drive. Can be formed.

In the present invention, the rotating body is provided with the rotating shaft protruding from both ends thereof, and the bearing is provided corresponding to each of the rotating shafts protruding from the rotating body. And
According to this aspect of the present invention, each of the rotating shafts protruding from both ends of the rotating body can be supported by the bearing with good slidability.

The present invention is also widely applied to a stepping motor provided with the above-described rotation drive device or an electronic device.
According to this aspect of the present invention, it is possible to realize a highly durable stepping motor and electronic device that rotate with good slidability over a long period of time and that are quiet.

  According to the present invention, it is possible to realize a rotary drive device, a stepping motor, and an electronic device that can effectively store a lubricant in a bearing portion of a rotary shaft.

1 is a schematic cross-sectional view of a rotary drive device according to Embodiment 1 of the present invention. The principal part expanded sectional view of the bearing part shown to the frame 1 of FIG. FIG. 2 is an exploded perspective view of the rotation drive device of FIG. 1. The schematic sectional drawing of the rotational drive apparatus which concerns on Embodiment 2 of this invention. The principal part expanded sectional view of the frame 2 bearing part of FIG. FIG. 5 is an exploded perspective view of the rotation drive device of FIG. 4. The schematic sectional drawing of the rotational drive apparatus which concerns on Embodiment 3 of this invention. The principal part expanded sectional view of the bearing part shown to the frame 3 of FIG. The schematic sectional drawing of the rotational drive apparatus which concerns on Embodiment 4 of this invention. The principal part expanded sectional view of the bearing part shown to the frame 4 of FIG. The perspective view of the bearing shape different from the bearing shape shown in Embodiment 1 of this invention. The perspective view of the bearing shape different from the bearing shape shown in Embodiment 1 of this invention.

Hereinafter, the present invention will be described in detail based on embodiments.
The present invention relates to a rotational drive device that rotationally drives a rotating body in a state where the rotating shaft of the rotating body is supported by a bearing, and in particular, lubricant such as oil leaks outside from the bearing more than necessary. The present invention relates to a bearing structure in which the lubricant can be effectively stored around the bearing portion, and the lubricant can be stably resupplied between the bearing portion in a stable manner.

  More specifically, the rotating body includes a rotating body from which one end of the rotating shaft protrudes, and a bearing having an engaging portion with which one end of the rotating shaft is rotatably engaged. In addition, an abutting portion that abuts on the end of the rotating body is provided around the engaging portion of the bearing. The contact portion protrudes from the bearing toward the end portion of the rotating body from which one end of the rotating shaft protrudes, and the tip thereof makes line contact with the end portion of the rotating body. The contact portion is provided with an outer diameter larger than that of the engagement portion and along the rotation direction of the rotating body. Between the contact portion and the rotation shaft, one end of the rotation shaft and the engagement portion are provided. A reservoir for storing the lubricant supplied to the engaging portion is provided.

  Here, since the abutting portion is a portion that is in sliding contact with the end of the rotating body as the rotating body rotates, if the contact portion is a line contact, the influence on the rotational drive can be reduced. Further, since the contact portion is in contact with the rotating body, in order to store a lubricant such as oil around the engaging portion of the rotating shaft, a wall portion that defines the storage space and Become. In other words, since the lubricant storage space can be formed around the rotating shaft at the end and the contact portion of the rotating body, the lubricant is stabilized between the rotating shaft and its bearing portion as the rotating body rotates. Thus, it is possible to supply (including resupply).

  In addition, by providing one or a plurality of such abutting portions concentrically around the engaging portion that receives the rotating shaft of the bearing, a reservoir that stores the lubricant while considering the influence on the rotational drive. It becomes possible to form multiple portions (storage spaces). Further, if a plurality of contact portions that are in line contact with the rotating body are provided in a multiple structure, that is, concentric circles, friction between the bearing and the rotating body can be reduced as compared with a case where all contact surfaces are provided.

  The contact portion may be provided integrally with the same material as the bearing, but may be provided separately from the bearing with a different material. In the latter case, the contact portion can be formed using a material having excellent slidability, for example, considering the slidability with the rotating body, regardless of the material of the bearing.

  Further, the contact portion that makes line contact with the rotating body is preferably provided continuously along the rotation direction of the rotating body. As a result, the abutting portion always abuts in the line contact state in the rotation direction of the rotating body, so that the influence on the rotational drive can be set smaller. The contact portion may be provided with a line contact portion and a surface contact portion along the rotation direction of the rotating body. Thereby, it becomes possible to improve the sealing property of the lubricant storage space while reducing the influence on the rotational drive.

  Further, if the structure for urging the rotating shaft against the above-mentioned bearing is adopted, the contact state between the end of the rotating body and the contact portion becomes stronger, so the storage space for storing the lubricant is highly accurate. Can be formed. For example, a rotating shaft is inserted into the rotating body, a bearing having the above-described contact portion is provided on one end side of the rotating shaft, and a spring or the like is provided between the other end side of the rotating shaft and the bearing. With a biasing means, the rotating shaft is pressed in the axial direction from the other end toward one end. In this case, the bearing on the one end side of the rotary shaft and the rotating body are in contact with each other with high accuracy (line contact or the like) without rattling by the contact portion. For this reason, it is possible to effectively prevent the lubricant from leaking from the contact portion.

  Since the rotating body is formed of a magnetic material such as a magnet, an annular intermediate member having good slidability (for example, a metal washer) is provided at the end of the rotating body in order to prevent contact with the contact portion. Etc.) are preferably joined together. As a result, it is possible to prevent the contact portion from directly slidingly contacting a magnetic body such as a magnet, and fluctuations in magnetic characteristics can be suppressed to a small level.

  Further, the abutment portion is preferably provided continuously in an annular shape around the rotation axis, but is preferably provided in the vicinity of the rotation shaft. Thereby, the influence on rotational drive can be set smaller. Further, the contact portion may be provided concentrically with the engaging portion of the bearing that receives the rotation shaft. As a result, the influence on the rotational drive can be minimized.

  Here, in the configuration of the rotary drive device described above, the bearing structure including the contact portion that is in line contact with the rotating body around the rotating shaft that protrudes mainly from one end of the rotating body has been described. May be applied to both ends of the rotating shaft that is inserted through the rotating body. Thereby, the both ends of a rotary body can be supported with sufficient slidability.

  Moreover, the front-end | tip part which penetrated the bearing among the rotating shafts is a sealing member (for example, plate member etc.) joined to the end surface of a bearing, and substantially seals the circumference | surroundings with a bearing part, for example. It is possible to take a receiving structure. With such a structure, the lubricant that temporarily protrudes from the bearing portion can be effectively held around the bearing portion. For this reason, since the lubricant is substantially sealed from the rotating body side and the sealing member side around the bearing portion, there is substantially no escape space and is held in the bearing portion and the vicinity thereof. Thereby, the stable rotational drive is realizable.

  As described above, the present invention can realize a high-torque rotational drive by preventing a decrease in torque by realizing a bearing structure with good slidability, and also can maintain a lubricant well and have high durability. In addition, it is possible to realize a rotary drive device that is also effective for noise reduction.

Hereinafter, embodiments of the present invention will be described in detail with specific examples with reference to the drawings.
<Embodiment 1>
1 to 3 are explanatory views showing the structure of a PM type stepping motor to which the present invention is applied. Reference numeral 10 denotes a rotating shaft 10 made of a non-magnetic material such as stainless steel that is rotatably supported. The rotor 17 includes rotating shafts 10 and magnets 9 that are alternately magnetized in the circumferential direction.

  Reference numerals 7 and 8 denote in-yokes made of, for example, a soft magnetic material having a plurality of comb teeth alternately arranged in the circumferential direction. Reference numerals 3 and 4 denote out yokes having a plurality of comb teeth alternately arranged in the circumferential direction and made of, for example, a soft magnetic material.

  Excitation coils 5 and 6 are mounted between the in-yokes 7 and 8 and the out-yokes 3 and 4 to excite the yokes. The stator 16 includes in-yokes 7 and 8, exciting coils 5 and 6, and out-yokes 3 and 4. Reference numeral 2 denotes a mold bearing at the rear end that is coaxially positioned by the outer diameter of the hollow cylindrical portion and the inner diameter of the out yokes 3 and 4.

  The rotor 17 is disposed coaxially within the stator 16 via a comb and a predetermined gap. The presser plate 1 is fixed in parallel to the end face of the out yoke 3, holds the rear end bearing 2 in the thrust direction, and has a flat shape in which the bearing and the shaft are enclosed in the yoke.

  The rotating shaft 10 and the presser plate 1 are not in contact with each other. The bearing 14 is fixed by caulking to a flange 15 that is a mounting plate, and is positioned by fitting the inner diameter of the out yoke 4 and the outer diameter of the bearing 14.

  A recess for installing the coil spring 12 is provided on the surface of the tip bearing 14 facing the magnet 9. The coil spring 12 is sandwiched between the washer 13 provided in the recess and the washer 11 on the end surface of the magnet 9 and contracted from its natural length. 12 is provided, and the magnet 9 is urged toward the rear end side of the motor by the restoring force of the coil spring.

  In this embodiment, the oil outflow prevention wall 2-A, which is provided on the surface of the rear end bearing 2 and is coaxial with the rotor 17 and has a spherical tip and a convex shape, and the magnet 9 are pressed in a line contact state. Oil (in this case, grease) is applied as a lubricant to the inner diameter portion of the rear end bearing 2 and the fitting portion 2-C of the rotary shaft 10 and is provided on the inner diameter side of the rear end bearing 2 on the magnet 9 side. In this structure, grease is accumulated in the space 2-B (hereinafter referred to as “grease damali”).

  Further, since the magnet 9 is urged to the rear end side by the coil spring 12 and the tip is in close contact with the spherical oil outflow prevention wall 2-A provided in the rear end bearing 2, the grease dam 2 -B can enclose grease by the magnet 9, the rotating shaft 10, and the annular and convex oil outflow prevention wall 2-A. The oil outflow prevention wall 2-A may be fixed to the rear end bearing 2 by a separate member from the bearing.

  In the above configuration, when the exciting coils 5 and 6 are energized, the in-yokes 7 and 8 and the out-yokes 3 and 4 are excited to be attracted to each comb tooth, and generate torque by repelling and attracting the magnet 1 magnetic pole. Then, the rotor 17 is driven to rotate and move in accordance with the energization of the exciting coils 5 and 6, and the driving force is transmitted from the rotating shaft 10 to the outside.

  In particular, during high-speed driving and continuous driving, the grease accumulated in the grease dam 2-B tends to scatter or flow out to the outer peripheral side due to the rotation of the rotating shaft 10, but the annular and convex oil outflow prevention wall 2-A Since the space in the thrust direction is closed by being pressed by the magnet 9, the grease does not flow out to the outer peripheral side from the oil outflow prevention wall 2 -A and stays in the grease pool.

  Since the inner diameter of the magnet 9 and the rotating shaft 10 are fixed by an adhesive, the fixed adhesive serves as a wall, so that grease does not flow out from the inner diameter side of the magnet, and a slight gap between the rotating shaft 10 and the rear end bearing 2. It becomes possible to supply grease only to the fitting part 2-C.

  Further, the space 2-D between the presser plate 1 and the rear end bearing 2 on the opposite side across the rear end bearing 2 is also a closed space, and can be a grease lumps for storing grease. In this case, a structure in which the grease 9-B between the magnet 9 and the rear end bearing 2 and the grease end 2-E of the rear end bearing 2 and the presser plate 1 sandwich the fitting portion 2-C between the rear end bearing 2 and the rotary shaft 10. Thus, since grease can be supplied semi-permanently to the fitting portion between the rear end bearing 2 and the rotary shaft 10, motor characteristics excellent in quietness and durability can be achieved.

<Embodiment 2>
4 to 6 are explanatory views showing the structure of a PM type stepping motor to which the present invention is applied.
In contrast to the first embodiment, the oil outflow prevention wall 2-A of the rear end bearing 2 is in line contact with the washer 18 installed between the magnet and the rear end bearing 2, and the surface portion 2-D of the rear end bearing 2 is the washer 18. Is in surface contact. Since the washer 18 is press-fitted into the rotating shaft 10 and the magnet 9 and the washer 18 rotate together, the anticorrosive film applied to the surface of the magnet is not affected by friction caused by direct rotation. Compared to the above, the effect of increasing the rust prevention power of the magnet 9 is expected.

<Embodiment 3>
7 to 8 are explanatory views showing the structure of a PM type stepping motor to which the present invention is applied.
In contrast to the second embodiment, the washer 18 and the rear end bearing 2 are in contact with each other on the surface other than the oil outflow prevention wall 2-A. When the washer 18 and the rear end bearing 2 are in contact with each other on the surface, when the magnet 9 is stopped, the damping force after the overshoot becomes stronger and quick positioning can be achieved, and improvement of vibration and noise of the magnet 9 is expected. Is done.

  In addition, since the surface contact portion 19 and the oil spill prevention wall 2-A are disposed through the space 20, even if oil leaks from the oil spill prevention wall, it does not adhere to the surface contact portion. . With this structure, unintended torque variation due to oil entering the surface contact portion can be eliminated.

<Embodiment 4>
9 to 10 are explanatory views showing the structure of a PM type stepping motor to which the present invention is applied. In contrast to the second embodiment, a plurality of oil outflow prevention walls are provided concentrically. In this case, four oil outflow prevention walls (21 to 24) are provided. As described above, the plurality of oil outflow prevention walls can surely prevent the oil from flowing out to the outer peripheral portion of the bearing.

<Embodiment 5>
FIG. 11 is an explanatory view showing the bearing shape of a PM type stepping motor to which the present invention is applied. In contrast to the annular oil spill prevention wall 2-A provided on the rear end bearing 2 of the first embodiment and having a spherical tip, an annular oil spill prevention wall 28 having an acute angle (triangle) shape is provided. ing. Since the tip has an acute angle, it comes into contact with the magnet in a more linear contact state, so the load in the rotational direction can be further reduced.

<Embodiment 6>
FIG. 12 is an explanatory view showing the bearing shape of a PM type stepping motor to which the present invention is applied. The tip of Embodiments 1 to 5 has a flat surface 30 at the tip of a part of the annular portion, whereas the tip of the annular portion is a sphere or an acute convex and communicating annular portion. Since all the lines are in contact with each other, the oil can be more reliably prevented from flowing out because it is blocked on a part of the surface.

1 Presser plate 2 Rear end bearing 2-A Grease outflow prevention wall 2-B Grease pool (magnet side)
2-C Fitting part of rotating shaft and bearing 2-D Grease pool (press plate side)
3 Outer yoke 4 Outer yoke 5 Coil 6 Coil 7 Inner yoke 8 Inner yoke 9 Rotor magnet
DESCRIPTION OF SYMBOLS 10 Rotating shaft 11 Washer 12 Coil spring 13 Washer 14 Tip bearing 15 Flange 16 Stator 17 Rotor 18 Washer 19 Surface contact part 20 Space 21 Grease outflow prevention wall 22 Grease outflow prevention wall 23 Grease outflow prevention wall 24 Grease outflow prevention wall 4
25 Space 26 Space 27 Space 28 Grease outflow prevention wall 29 having a sharp tip (triangle) shape 29 Line contact portion (6 locations)
30 surface contact parts (6 locations)

Claims (10)

A rotating body with one end of the rotating shaft protruding;
A bearing having an engaging portion with which one end of the rotating shaft is rotatably engaged;
Around the engagement portion of the bearing, there is an abutting portion that protrudes toward the end of the rotating body from which one end of the rotating shaft protrudes and whose tip is in line contact with the end of the rotating body. , Provided with an outer diameter larger than the engaging portion and along the rotation direction of the rotating body,
A rotation portion is provided between the contact portion and the rotation shaft, and a storage portion for storing a lubricant supplied to an engagement portion between one end of the rotation shaft and the engagement portion is provided. Drive device. An annular intermediate member is integrally joined to the end of the rotating body,
The rotary drive device according to claim 1, wherein the contact portion of the bearing is in line contact with the intermediate member.   The rotary drive device according to claim 1, wherein the contact portion is provided concentrically with the engagement portion of the bearing.   The rotary drive device according to claim 3, wherein a plurality of the contact portions are provided concentrically with the engagement portion of the bearing.   The rotary drive device according to claim 1, wherein the contact portion is provided separately from the bearing.   The rotary drive device according to claim 1, wherein the contact portion is provided continuously along a rotation direction of the rotating body.   6. The rotational drive according to claim 1, wherein the contact portion is provided with a line-contact portion and a surface-contact portion along the rotation direction of the rotating body. apparatus. The rotating body is provided with the rotating shafts protruding from both ends thereof,
The rotation drive device according to any one of claims 1 to 7, wherein the bearing is provided corresponding to each of the rotation shafts protruding from the rotating body.   A stepping motor comprising the rotation drive device according to any one of claims 1 to 8.   An electronic apparatus comprising the rotation drive device according to claim 1.

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